Accuracy characteristics of the electronics of waverider buoys used in the ARSLOE

During the Atlantic Remote Sensing Land Ocean Experiment (ARSLOE), October-November, 1980, a large number of meteorological and oceanographic instruments, especially wave-measurement instruments, were deployed in the ocean near the Army Corps of Engineers Pier, Duck, NC. About nine Waverider buoys were deployed in an approximately rectangular pattern, about 30 km wide by 40 km seaward. The Waveriders were an accepted reference for study of other wave-measurement instrument systems. Almost all of the Waverider buoys were calibrated on the rotating-arm facility of the NOAA, Engineering Support Office. Pre- and post-deployment calibrations formed the basis for tables and equations for correction of the Waverider measurements. The calibrations discussed here established that the Waveriders were measuring lower than specification, averaging about 5 percent low (10 percent for variance spectra coefficients.) Corrections for effects of fluctuations in water temperature on Waverider sensitivity were required and are provided. The manufacturer's modification to prevent future drift in sensitivity is also described.     

北美内陆西部白垩纪脊椎动物生物年代学

北美西部内陆白垩纪的脊椎动物生物年代学的研究始于19世纪90年代。前人建议的期,即陆生脊椎动物"期"或陆生哺乳动物"期"名已过十二个,但其中具有精确的定义者甚少,仅有少量的建议受到广泛认可和使用。本文定义或重新定义了10个陆生脊椎动物"期",包括了西部内陆从最老至最新的全部白垩纪—Comobluffian期(～提塘期至欧特里沃期)、Buffalogapian期(～巴列姆期至早阿普特期)、Cashenranchian期(～早阿普特期至晚阿尔布期)、Mussentuchian期(～晚阿尔布期至塞诺曼期)、Fencelakean期(土伦期至晚塞农期)、Aquilan期(～晚塞农期至早坎潘期)、Judithian期(～中坎潘期)、Kirtlandian期(～晚坎潘期)、Edmontonian期(～坎潘期末期至早马斯特里赫特期)以及Lancian期(～早马斯特里赫特期晚期)。每一个"期"的开始由一种恐龙或哺乳动物种类的首现来定义,而其结束由后续的"期"的开始来定义。这样定义的脊椎动物生物年代代表了完整的白垩纪时间表。但有些时间段(尤其是Neocomian(尼欧克姆期)的大部分以及部分"中"白垩世的一部分)缺乏足够的脊椎动物化石特征。这些白垩纪陆生脊椎动物"期"构成了一个能使北美西部内陆的脊椎动物的演化历史得以序和解释年代表。     

On the importance of advection in determining the local isotopic composition of the mantle

The equations for isotopic evolution in a deforming medium are derived and used to show that the local isotopic composition of the mantle depends primarily on the advection of heterogeneities by the flow field. Various examples of the role of advection are given using a two-scale model of mantle convection. The effect of small-scale flows, which have dimensions smaller than the plates themselves, is to convert any initially localized heterogeneity into thin spiral sheets. The isotopic properties of erupted lavas will depend on the relative size of the zone of partial melt to the spacing between such sheets. An idealized model for⁸⁷Sr/⁸⁶Sr variations from Pacific islands and the covariation of¹⁴³Nd/¹⁴⁴Nd-⁸⁷Sr/⁸⁶Sr is based on the combined effect of isotopic fluxes at subduction zones and advection by the return flow under the moving lithospheric plates.     

Dynamical geochemistry of the Hawaiian plume

This paper presents a simple dynamical model for melting and trace element distribution in the Hawaiian mantle plume. I model the plume as a partially molten stagnation point flow against the oceanic lithosphere, and obtain solutions for the temperature, melt migration rate, and trace element concentration within it. Trace element concentrations in the melt exceed simple batch melting predictions by up to 70%. The magnitude of this effect depends strongly on the solid-melt partition coefficientK. Trace elements with differentK therefore experience a “dynamical fractionation” within the plume, and incompatible trace element ratios such asLa/Ce always exceed the batch melting predictions. I suggest a simple model for plume-lithosphere interaction in which melts from these two sources mix in proportions determined by thermodynamic constraints. The model can explain the composition of basalts from Haleakala if the degree of melting of the lithosphereF₁ decreases with time from roughly 10% for tholeiites to 2% for alkalic basalts. These values are considerably higher than previous estimates ofF₁ < 1%, and imply correspondingly smaller and more realistic values ( 10 km) for the thickness of the melted part of the lithosphere. Partial melting of additional depleted sources such as the asthenosphere is therefore not required by the Haleakala data. Estimates ofF₁ are highly sensitive to the values chosen for the partition coefficients, however, and should therefore be interpreted with caution.